Controlling and stabilizing device for helicopters



' June 2, 1925.

E. OEHMICHEN CONTROLLING AND STABILIZING DEVICE FOR HELICOPTERS Filed July 26, 1923 2 Sheets-Sheet 1 14 Z25 r gy s June 2, 1925.

' E. -.OEHMIC HEN CONTROLLING AND STABILIZING DEVICE F011 HELICOPTERS Filed July 26, 1923 2 Shoets-;-Sheet 2 I22 Were/3'01 132827229 OeZZamicZezz Patented June- 2, 1925 1 UNITED STATES PATENT orr ca.

ETIENNE onnmcnmr, or varm'rennr, rmucn.

CONTROLLING am) s'ranmzme DEVICE ron HELICOPTERS.

Application filed July 26, 1928. Serial No. 653,956.

To all whom it may concern:

Be it known that I, ETIENNE OEHMICHEN,

a citizen of the Republic of France,, and

against the displacement of the center of. pressure below the propellers when the ma chine is traveling forward, or what amounts to the same, when it. is moving against a lateral, wind. Further, it becomes difiicult to regulate the altitude and the landing of the'machine, for these depend solely upon the speed of rotation of the sustaining propellers and hence upon the opening of the gas inlet.

My invention relates to a device whereby all these drawbacks will be obviated. It consists in principle in the addition to the helicopter of a certain even number of small auxiliary propellers with vertical shaft and variable pitch, termed evolution propellers, which rotate in pairs in opposite directions, and jare. driven from the main shafting'or by a separate engine. Thepilot makes use of devices for controlling their angle of incidence, and is enabled to act upon each propeller by means of. a specia device which 'will be further described.

In principle, the evolution propellersare disposed symmetrically in pairs about the' Flat center of gravity of the machine. blades are preferably used, because they are required to operate under positive or negative incidence. The inclination and straight: ening ofthe machine may in particular be controlled by a single further control the movements of ascent and of stabilizing am to altitude anddescent; On the other hand, as' will be further stated, the said single controlling-device may also be used to effect steering or orientation'of the machine.

Theappended drawings which are given by way of exampleillustrate an embodiment of the invention. a i Fig. is a diagrammatlc 'perspectwe v1ew.

evice' which may.

of a helicopter having a set of auxiliary or evolution propellers.

Fig- 2 is a separate perspective view of the evolution propellers used for the inclination and straightening of the machine- F 3 shows the details of adevice for controlling the incidence of the blades of said propellers.

Fig. 4 is a longitudinal section of said device.

Fig 5is a perspective view of the same.

Thelhelicopter is provided for inclination and .straightening purposes with. four like evolution propellers E E E E, disposed at the 'vertices of a square whose center is at C. The angle of incidence of the said eyolution propellers is controlled by. the p j of f1 f n f2 f2 fa f sa f4 f4; sald wires are dlsposed upon sheaves 9 g 9, 9' 9 9' 9 g,.mounted on the-tube T, Fi -3-to 5, and proceed within the said tube, hr ai ng attached to a sliding member T,

mounted 'on a control rod t, at the points 1, 2, 3, 4. The said tube is pivoted by means of a ball-and-socket. joint S having a fixed-center O; the member t is slidable within the tube T. With the said tube in the fixed position, should the sliding member bemoved longitudinally in the upward direction this .willcause the device to draw by the same amount upon the wires f,, f, 7",, f and .to slacken the wires f f f f i in like manner, so that the pilot can impart to the four propellers variations of incidence having the same magnitude and direction. But if the tube T is inclined for instance in the direction S Fig. 4, the

wires f, f; will be stretched and the wires i f, released, so as to effect the differential control of the two propellers E 151,, i. e.

they will be given variations of incidence of equal value and in opposite directions.

.The principle ofmy invention thus becomes clearly apparent. With the machine in equilibrium during the-flight, the pilot controls the rise and descent by the slidin of the rod t he controls the inclination an straightening of the machine by inclining the whole aggregate tT upon S, i. e. aboutthe center 0, in the convenientdirectiont These two operations can be performed simultaneously, and by mounting upon t a hand wheel V the pilot can even effect the steering of the machine; it is simply necessary'to dispose upon the tube T a revoluble support, for instance a fork having the two movement of rotation of the fork B B,

on the axis XX is combined by suitable means with the rotation of the said hand wheel on the same axis.

Fig. 5 clearly indicates a theoretical solution of this question. B B carries a toothed quadrant n engaging a pinion n keyed to the shaft a; on the said shaft is mounted a second pinion a engaging a toothed ring a. The latter is rotated by the hand wheel by means of a sliding member V such as a longkey, fork or the like. The hand wheel turns about t but without actuating it, and can only move the same in the direction XX In this event the wires 03,, d (steering control wires) will only be lengthened or shortened when the hand wheel is turned on its axis; all the other movements of the wheel (for rising, descent or inclination) will in the first two cases produce no motion of e, and (2,, and in the latter case will raise one of the points e, or 6 whilst the other will be equally lowered.

The wires d 03, control the steering of the machine, which may be carried out by the surfaces D mounted rearwardly of the tractive propeller, or by the secondary evolution propellers E',, E with horizontal axis and variable incidence.

Obviously the principle of the invention will not depend upon the execution of the various details, but is based upon the use of auxiliary propellers in any suitable number,

and preferably an even number, so disposed as to provide for the rise and descent of the machine as well as the inclination and the straightening, by means of the single central controlling device, which is operated solely according to the natural reflex movesteering control, so that the pilot can execute. all the operations without handling any other control device except the hand wheel V actuating the rod t.

It is evident that the principle of the invention will remain the same if instead of employing two like propellers per pair, use is made of unequal propellers mounted at different distances from the center of gravity, or further, if a somewhat larger propeller is combined with two or more smaller propellers having the same total efli'eet as the former. The principle of the invention will not be modified for this reason. The

'only drawback in the use of une ual propellers consists in the production 0 unequal couples of antirotation, so that the whole machine frame would turn about, and also ponents when controlling so as to incline or a resultant couple acting'against the rotation may be produced, and such will be the case for example when the pilot operates by drawing upon the rod t and inclining it at the same time- One propeller of a given pair will thus have a resistance which is not compensated by the resistance of the other, so that it becomes necessary to counteract the effect of antirotation. But this may be readily carried out, if the machine comprises evolution propellers with horizontal shaft, by turning the steering hand wheel controlling the same, and the wheel may also serve to control the deflecting planes disposed behind the auxiliary propellers.

.During the flight, the action of the steering rudder will be sufficient.

, To recapitulate, my invention consists in the addition to the arrangement which is capable of sustaining the helicopter, of a suitable number of auxiliary propellers with variable and reversible incidence, which are controlled by a central device providing for addition and subtraction of ascensionaleflortsas well as effects of inclination and straightening of the machine. The controls may be separate or disposed in the shape of a common controlling device which may also comprise the controls for steering, turning of the machine, or resistance to the antirotation. In the last two cases, a certain numberof the evolution propellers will have horizontal or oblique shafts, such as E and E,, Fig. 1, or I may also employ deflectors laced behind the propellers such as d Fig. 1, or like correcting means which are disposed below the evolution propellers or below the main sustaining arrangement.

In its widest application, my said apparatus can be employed, without requirmg the pilot to remove his hands or to make use of his feet, for the various operations of 1. In a helicopter apparatus, the combina tion of a main prope ler for sustaining the apparatus in the air, and whereof the arms passes through the center of gravity of the apparatus, a plurality of auxiliary propellers in constant rotation during the opera.-

the production of involuntary vertical comcomprising flat blades whose incidence can rections about a center of oscillation, means for varying the incidence of the blades of the said auxiliary propellers, said means being so connected with the said central lever that the movement of the latter in-a given direction will vary the incidence of the blades of a given pair of auxiliary propellers.

2.'A helicopter comprisin in combination means for sustaining t e machine in v the air, a plurality of auxiliary ropellers wherein the incidence of the bla es can be modified or reversed, a tube pivoting in all directions about one of its points, a sliding member slidable within the aid tube, pairs of wires attached to said iding member and extending longitudinally through the tube, thetwo wires of each pair being attached to one of the said auxiliary propel-, lers and adapted to modify the incidence of the respective blades when the said sliding member 'is displaced in the tube, sheaves moiinted on the said tube for guiding the said wires when proceeding out of the tube, the two sheaves corresponding to a given pair of wires and to a given ropeller bein situated on opposite sides 0 the said sli ing member, and a controlling rod secured to the said sliding member and extending I through the tube and outwardly of the same.

3. A helicopter com rising in combination means for sustaining the machine in the air, a plurality of auxiliar ropellers wherein the incidence of the bill es can be modified or reversed, a'tube'pivoting in all directions aboutone of its points, a sliding member slidable within the said tube, pairs of wires attached to said sliding member and extending longitudinally -through the tube, the two wires of each pair belng at.-

.tached to one of the said auxiliary propellers'and adapted to modify the incidence of the respective blades when the said sliding member plS displaced in the tube, sheaves mounted on the said tube for guiding the said wires when proceeding out of the tube, the two sheaves corresponding to a given air ofwires and to a given propeller bemg situated on opposite sides of the said sliding member, a controlling rod secured to the said slidin member and extending through the tu and outwardly of the same, a fork loosely revoluble upon the said tube, the ends of the arms -of said fork being situated upon a straight line passing through the pivoting center of the tube, controlling means for rotating the said fork, a pair of wires attached to the ends of the fork and secured to the respective auxiliary pfppellers wherein the incidence of the" es can be modified or reversed, said controlling means being likewise connected with said controlling rod whereby the latter shall be movable solely in the longitudinal direction. a I o In testimony that'I-claim the foregoing as my invention I have signed myname in 1a presence of a subscribingv witness.

' ETIENNE OEHMICHEN. Witness:

Maumcn Rom.- 

